lox-derive-v0.1.0-alpha.5

Added

• (lox-test-utils) add ApproxEq derive macro
• (lox-derive) implement OffsetProvider derive macro

Other

• update SPDX headers and add helper script
• make Lox REUSE-compliant
• get rid of float_eq and lox_math::is_close
• (lox-units) make Angle value private